The present invention relates to energy generation in which energy generated by detonating fuel, air and/or oxidant can be converted to electrical energy. In particular, the present invention combines a combustion chamber coupled to an air inlet and a fuel source and a means for converting the energy of the detonation into electrical energy.
Many researchers have encountered difficulties in attempting to study and characterize the performance of pulsed detonation devices. Some investigators have attempted to initiate detonation in mixtures with insufficient amounts of energy, and have therefore unwittingly created deflagrative burning devices. Typically, detonation was not achieved at all, or was achieved only after a lengthy transition from a deflagration.
Unsteady pulse deflagration combustors have been under investigation for some time, but as of yet these devices have failed to provide enough of a performance gain over typical steady state combustors to warrant wide spread research, development, and commercialization. The pulse detonation combustor of the present invention not only significantly out-performs the prior art devices, but also benefits greatly from related pulse detonation efforts by Applicant underway in other fields.
A focused research and development program is underway by the Applicant to successfully commercialize several applications for pulse detonation combustion. A majority of the effort has been focused in the areas of aerospace propulsion and materials science. Patent applications have been filed and/or patents have issued for these inventions. Specifically, U.S. application Ser. No. 08/205,505, now U.S. Pat. No. 5,513,489, and U.S. application Ser. No. 08/613,194, filed Mar. 8, 1996, are incorporated by reference along with all information and references contained therein.
A novel, patented multiple tube engine concept has been developed for airbreathing propulsion applications. Applicant's design allows the system to operate at higher cycle frequencies and lower inlet losses than previous concepts. It consists of several PDE combustors or detonation chambers coupled to an air inlet and fuel source via a rotary valve. The valve serves to isolate the steady operation of the air inlets and fuel systems from the unsteady nature of the detonation process. The rotary valve allows some of the PDE combustion chambers to be fueled while detonation occurs in other PDE combustors. In this way, the fueling system can operate in a steady state mode in conjunction with an unsteady combustion process. Detonation initiation occurs through a co-located fuel/oxygen pre-detonation zone located at the top of each combustor.
Intermittent combustion engines in the form of pulse jet engines, such as those in U.S. Pat. No. 2,930,196 to Hertzberg, et al., U.S. Pat. No. 2,515,644 to Goddard, and U.S. Pat. No. 3,008,292 to Logan, are known. Pulse combustion in these prior art engines is deflagrative in nature. A deflagration combustion process results in propagation velocities on the order of a few meters per second while detonative combustion results in propagation velocities on the order of several thousands of meters per second. The use of a detonation combustion process in an engine has been suggested. For example, U.S. Pat. No. 4,741,154 to Eidelman shows a rotary engine using a detonation process.
Other gas based combustion systems for gas turbine applications include steady state combustors and pulse deflagrative combustors. Conventional steady state gas burners have been in use for years and have been described extensively in the literature. These devices are well understood and have proven reliable and efficient.
Pulse deflagration combustion systems are described extensively in the literature for various applications. Recent efforts have concentrated on transferring the technology to gas turbine applications. The pulse combustors developed thus far have relied on deflagrative combustion principles. Pulse combustor devices have demonstrated some of the inherent advantages of unsteady combustion which include: high combustion efficiency, high heat release, and low NO.sub.X production levels. The system described in this application is based on detonative combustion, which is significantly more efficient than deflagration combustion.